ext2/xip: refuse to change xip flag during remount with busy inodes
[linux-2.6.git] / fs / ext2 / super.c
1 /*
2  *  linux/fs/ext2/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  */
18
19 #include <linux/module.h>
20 #include <linux/string.h>
21 #include <linux/fs.h>
22 #include <linux/slab.h>
23 #include <linux/init.h>
24 #include <linux/blkdev.h>
25 #include <linux/parser.h>
26 #include <linux/random.h>
27 #include <linux/buffer_head.h>
28 #include <linux/exportfs.h>
29 #include <linux/smp_lock.h>
30 #include <linux/vfs.h>
31 #include <linux/seq_file.h>
32 #include <linux/mount.h>
33 #include <linux/log2.h>
34 #include <linux/quotaops.h>
35 #include <asm/uaccess.h>
36 #include "ext2.h"
37 #include "xattr.h"
38 #include "acl.h"
39 #include "xip.h"
40
41 static void ext2_sync_super(struct super_block *sb,
42                             struct ext2_super_block *es);
43 static int ext2_remount (struct super_block * sb, int * flags, char * data);
44 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
45
46 void ext2_error (struct super_block * sb, const char * function,
47                  const char * fmt, ...)
48 {
49         va_list args;
50         struct ext2_sb_info *sbi = EXT2_SB(sb);
51         struct ext2_super_block *es = sbi->s_es;
52
53         if (!(sb->s_flags & MS_RDONLY)) {
54                 sbi->s_mount_state |= EXT2_ERROR_FS;
55                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
56                 ext2_sync_super(sb, es);
57         }
58
59         va_start(args, fmt);
60         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
61         vprintk(fmt, args);
62         printk("\n");
63         va_end(args);
64
65         if (test_opt(sb, ERRORS_PANIC))
66                 panic("EXT2-fs panic from previous error\n");
67         if (test_opt(sb, ERRORS_RO)) {
68                 printk("Remounting filesystem read-only\n");
69                 sb->s_flags |= MS_RDONLY;
70         }
71 }
72
73 void ext2_warning (struct super_block * sb, const char * function,
74                    const char * fmt, ...)
75 {
76         va_list args;
77
78         va_start(args, fmt);
79         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
80                sb->s_id, function);
81         vprintk(fmt, args);
82         printk("\n");
83         va_end(args);
84 }
85
86 void ext2_update_dynamic_rev(struct super_block *sb)
87 {
88         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
89
90         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
91                 return;
92
93         ext2_warning(sb, __func__,
94                      "updating to rev %d because of new feature flag, "
95                      "running e2fsck is recommended",
96                      EXT2_DYNAMIC_REV);
97
98         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
99         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
100         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
101         /* leave es->s_feature_*compat flags alone */
102         /* es->s_uuid will be set by e2fsck if empty */
103
104         /*
105          * The rest of the superblock fields should be zero, and if not it
106          * means they are likely already in use, so leave them alone.  We
107          * can leave it up to e2fsck to clean up any inconsistencies there.
108          */
109 }
110
111 static void ext2_put_super (struct super_block * sb)
112 {
113         int db_count;
114         int i;
115         struct ext2_sb_info *sbi = EXT2_SB(sb);
116
117         ext2_xattr_put_super(sb);
118         if (!(sb->s_flags & MS_RDONLY)) {
119                 struct ext2_super_block *es = sbi->s_es;
120
121                 es->s_state = cpu_to_le16(sbi->s_mount_state);
122                 ext2_sync_super(sb, es);
123         }
124         db_count = sbi->s_gdb_count;
125         for (i = 0; i < db_count; i++)
126                 if (sbi->s_group_desc[i])
127                         brelse (sbi->s_group_desc[i]);
128         kfree(sbi->s_group_desc);
129         kfree(sbi->s_debts);
130         percpu_counter_destroy(&sbi->s_freeblocks_counter);
131         percpu_counter_destroy(&sbi->s_freeinodes_counter);
132         percpu_counter_destroy(&sbi->s_dirs_counter);
133         brelse (sbi->s_sbh);
134         sb->s_fs_info = NULL;
135         kfree(sbi->s_blockgroup_lock);
136         kfree(sbi);
137
138         return;
139 }
140
141 static struct kmem_cache * ext2_inode_cachep;
142
143 static struct inode *ext2_alloc_inode(struct super_block *sb)
144 {
145         struct ext2_inode_info *ei;
146         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
147         if (!ei)
148                 return NULL;
149 #ifdef CONFIG_EXT2_FS_POSIX_ACL
150         ei->i_acl = EXT2_ACL_NOT_CACHED;
151         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
152 #endif
153         ei->i_block_alloc_info = NULL;
154         ei->vfs_inode.i_version = 1;
155         return &ei->vfs_inode;
156 }
157
158 static void ext2_destroy_inode(struct inode *inode)
159 {
160         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
161 }
162
163 static void init_once(void *foo)
164 {
165         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
166
167         rwlock_init(&ei->i_meta_lock);
168 #ifdef CONFIG_EXT2_FS_XATTR
169         init_rwsem(&ei->xattr_sem);
170 #endif
171         mutex_init(&ei->truncate_mutex);
172         inode_init_once(&ei->vfs_inode);
173 }
174
175 static int init_inodecache(void)
176 {
177         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
178                                              sizeof(struct ext2_inode_info),
179                                              0, (SLAB_RECLAIM_ACCOUNT|
180                                                 SLAB_MEM_SPREAD),
181                                              init_once);
182         if (ext2_inode_cachep == NULL)
183                 return -ENOMEM;
184         return 0;
185 }
186
187 static void destroy_inodecache(void)
188 {
189         kmem_cache_destroy(ext2_inode_cachep);
190 }
191
192 static void ext2_clear_inode(struct inode *inode)
193 {
194         struct ext2_block_alloc_info *rsv = EXT2_I(inode)->i_block_alloc_info;
195 #ifdef CONFIG_EXT2_FS_POSIX_ACL
196         struct ext2_inode_info *ei = EXT2_I(inode);
197
198         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
199                 posix_acl_release(ei->i_acl);
200                 ei->i_acl = EXT2_ACL_NOT_CACHED;
201         }
202         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
203                 posix_acl_release(ei->i_default_acl);
204                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
205         }
206 #endif
207         ext2_discard_reservation(inode);
208         EXT2_I(inode)->i_block_alloc_info = NULL;
209         if (unlikely(rsv))
210                 kfree(rsv);
211 }
212
213 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
214 {
215         struct super_block *sb = vfs->mnt_sb;
216         struct ext2_sb_info *sbi = EXT2_SB(sb);
217         struct ext2_super_block *es = sbi->s_es;
218         unsigned long def_mount_opts;
219
220         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
221
222         if (sbi->s_sb_block != 1)
223                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
224         if (test_opt(sb, MINIX_DF))
225                 seq_puts(seq, ",minixdf");
226         if (test_opt(sb, GRPID))
227                 seq_puts(seq, ",grpid");
228         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
229                 seq_puts(seq, ",nogrpid");
230         if (sbi->s_resuid != EXT2_DEF_RESUID ||
231             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
232                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
233         }
234         if (sbi->s_resgid != EXT2_DEF_RESGID ||
235             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
236                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
237         }
238         if (test_opt(sb, ERRORS_RO)) {
239                 int def_errors = le16_to_cpu(es->s_errors);
240
241                 if (def_errors == EXT2_ERRORS_PANIC ||
242                     def_errors == EXT2_ERRORS_CONTINUE) {
243                         seq_puts(seq, ",errors=remount-ro");
244                 }
245         }
246         if (test_opt(sb, ERRORS_CONT))
247                 seq_puts(seq, ",errors=continue");
248         if (test_opt(sb, ERRORS_PANIC))
249                 seq_puts(seq, ",errors=panic");
250         if (test_opt(sb, NO_UID32))
251                 seq_puts(seq, ",nouid32");
252         if (test_opt(sb, DEBUG))
253                 seq_puts(seq, ",debug");
254         if (test_opt(sb, OLDALLOC))
255                 seq_puts(seq, ",oldalloc");
256
257 #ifdef CONFIG_EXT2_FS_XATTR
258         if (test_opt(sb, XATTR_USER))
259                 seq_puts(seq, ",user_xattr");
260         if (!test_opt(sb, XATTR_USER) &&
261             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
262                 seq_puts(seq, ",nouser_xattr");
263         }
264 #endif
265
266 #ifdef CONFIG_EXT2_FS_POSIX_ACL
267         if (test_opt(sb, POSIX_ACL))
268                 seq_puts(seq, ",acl");
269         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
270                 seq_puts(seq, ",noacl");
271 #endif
272
273         if (test_opt(sb, NOBH))
274                 seq_puts(seq, ",nobh");
275
276 #if defined(CONFIG_QUOTA)
277         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
278                 seq_puts(seq, ",usrquota");
279
280         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
281                 seq_puts(seq, ",grpquota");
282 #endif
283
284 #if defined(CONFIG_EXT2_FS_XIP)
285         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
286                 seq_puts(seq, ",xip");
287 #endif
288
289         if (!test_opt(sb, RESERVATION))
290                 seq_puts(seq, ",noreservation");
291
292         return 0;
293 }
294
295 #ifdef CONFIG_QUOTA
296 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
297 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
298 #endif
299
300 static const struct super_operations ext2_sops = {
301         .alloc_inode    = ext2_alloc_inode,
302         .destroy_inode  = ext2_destroy_inode,
303         .write_inode    = ext2_write_inode,
304         .delete_inode   = ext2_delete_inode,
305         .put_super      = ext2_put_super,
306         .write_super    = ext2_write_super,
307         .statfs         = ext2_statfs,
308         .remount_fs     = ext2_remount,
309         .clear_inode    = ext2_clear_inode,
310         .show_options   = ext2_show_options,
311 #ifdef CONFIG_QUOTA
312         .quota_read     = ext2_quota_read,
313         .quota_write    = ext2_quota_write,
314 #endif
315 };
316
317 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
318                 u64 ino, u32 generation)
319 {
320         struct inode *inode;
321
322         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
323                 return ERR_PTR(-ESTALE);
324         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
325                 return ERR_PTR(-ESTALE);
326
327         /* iget isn't really right if the inode is currently unallocated!!
328          * ext2_read_inode currently does appropriate checks, but
329          * it might be "neater" to call ext2_get_inode first and check
330          * if the inode is valid.....
331          */
332         inode = ext2_iget(sb, ino);
333         if (IS_ERR(inode))
334                 return ERR_CAST(inode);
335         if (generation && inode->i_generation != generation) {
336                 /* we didn't find the right inode.. */
337                 iput(inode);
338                 return ERR_PTR(-ESTALE);
339         }
340         return inode;
341 }
342
343 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
344                 int fh_len, int fh_type)
345 {
346         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
347                                     ext2_nfs_get_inode);
348 }
349
350 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
351                 int fh_len, int fh_type)
352 {
353         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
354                                     ext2_nfs_get_inode);
355 }
356
357 /* Yes, most of these are left as NULL!!
358  * A NULL value implies the default, which works with ext2-like file
359  * systems, but can be improved upon.
360  * Currently only get_parent is required.
361  */
362 static const struct export_operations ext2_export_ops = {
363         .fh_to_dentry = ext2_fh_to_dentry,
364         .fh_to_parent = ext2_fh_to_parent,
365         .get_parent = ext2_get_parent,
366 };
367
368 static unsigned long get_sb_block(void **data)
369 {
370         unsigned long   sb_block;
371         char            *options = (char *) *data;
372
373         if (!options || strncmp(options, "sb=", 3) != 0)
374                 return 1;       /* Default location */
375         options += 3;
376         sb_block = simple_strtoul(options, &options, 0);
377         if (*options && *options != ',') {
378                 printk("EXT2-fs: Invalid sb specification: %s\n",
379                        (char *) *data);
380                 return 1;
381         }
382         if (*options == ',')
383                 options++;
384         *data = (void *) options;
385         return sb_block;
386 }
387
388 enum {
389         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
390         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
391         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
392         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
393         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
394         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
395 };
396
397 static const match_table_t tokens = {
398         {Opt_bsd_df, "bsddf"},
399         {Opt_minix_df, "minixdf"},
400         {Opt_grpid, "grpid"},
401         {Opt_grpid, "bsdgroups"},
402         {Opt_nogrpid, "nogrpid"},
403         {Opt_nogrpid, "sysvgroups"},
404         {Opt_resgid, "resgid=%u"},
405         {Opt_resuid, "resuid=%u"},
406         {Opt_sb, "sb=%u"},
407         {Opt_err_cont, "errors=continue"},
408         {Opt_err_panic, "errors=panic"},
409         {Opt_err_ro, "errors=remount-ro"},
410         {Opt_nouid32, "nouid32"},
411         {Opt_nocheck, "check=none"},
412         {Opt_nocheck, "nocheck"},
413         {Opt_debug, "debug"},
414         {Opt_oldalloc, "oldalloc"},
415         {Opt_orlov, "orlov"},
416         {Opt_nobh, "nobh"},
417         {Opt_user_xattr, "user_xattr"},
418         {Opt_nouser_xattr, "nouser_xattr"},
419         {Opt_acl, "acl"},
420         {Opt_noacl, "noacl"},
421         {Opt_xip, "xip"},
422         {Opt_grpquota, "grpquota"},
423         {Opt_ignore, "noquota"},
424         {Opt_quota, "quota"},
425         {Opt_usrquota, "usrquota"},
426         {Opt_reservation, "reservation"},
427         {Opt_noreservation, "noreservation"},
428         {Opt_err, NULL}
429 };
430
431 static int parse_options (char * options,
432                           struct ext2_sb_info *sbi)
433 {
434         char * p;
435         substring_t args[MAX_OPT_ARGS];
436         int option;
437
438         if (!options)
439                 return 1;
440
441         while ((p = strsep (&options, ",")) != NULL) {
442                 int token;
443                 if (!*p)
444                         continue;
445
446                 token = match_token(p, tokens, args);
447                 switch (token) {
448                 case Opt_bsd_df:
449                         clear_opt (sbi->s_mount_opt, MINIX_DF);
450                         break;
451                 case Opt_minix_df:
452                         set_opt (sbi->s_mount_opt, MINIX_DF);
453                         break;
454                 case Opt_grpid:
455                         set_opt (sbi->s_mount_opt, GRPID);
456                         break;
457                 case Opt_nogrpid:
458                         clear_opt (sbi->s_mount_opt, GRPID);
459                         break;
460                 case Opt_resuid:
461                         if (match_int(&args[0], &option))
462                                 return 0;
463                         sbi->s_resuid = option;
464                         break;
465                 case Opt_resgid:
466                         if (match_int(&args[0], &option))
467                                 return 0;
468                         sbi->s_resgid = option;
469                         break;
470                 case Opt_sb:
471                         /* handled by get_sb_block() instead of here */
472                         /* *sb_block = match_int(&args[0]); */
473                         break;
474                 case Opt_err_panic:
475                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
476                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
477                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
478                         break;
479                 case Opt_err_ro:
480                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
481                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
482                         set_opt (sbi->s_mount_opt, ERRORS_RO);
483                         break;
484                 case Opt_err_cont:
485                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
486                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
487                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
488                         break;
489                 case Opt_nouid32:
490                         set_opt (sbi->s_mount_opt, NO_UID32);
491                         break;
492                 case Opt_nocheck:
493                         clear_opt (sbi->s_mount_opt, CHECK);
494                         break;
495                 case Opt_debug:
496                         set_opt (sbi->s_mount_opt, DEBUG);
497                         break;
498                 case Opt_oldalloc:
499                         set_opt (sbi->s_mount_opt, OLDALLOC);
500                         break;
501                 case Opt_orlov:
502                         clear_opt (sbi->s_mount_opt, OLDALLOC);
503                         break;
504                 case Opt_nobh:
505                         set_opt (sbi->s_mount_opt, NOBH);
506                         break;
507 #ifdef CONFIG_EXT2_FS_XATTR
508                 case Opt_user_xattr:
509                         set_opt (sbi->s_mount_opt, XATTR_USER);
510                         break;
511                 case Opt_nouser_xattr:
512                         clear_opt (sbi->s_mount_opt, XATTR_USER);
513                         break;
514 #else
515                 case Opt_user_xattr:
516                 case Opt_nouser_xattr:
517                         printk("EXT2 (no)user_xattr options not supported\n");
518                         break;
519 #endif
520 #ifdef CONFIG_EXT2_FS_POSIX_ACL
521                 case Opt_acl:
522                         set_opt(sbi->s_mount_opt, POSIX_ACL);
523                         break;
524                 case Opt_noacl:
525                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
526                         break;
527 #else
528                 case Opt_acl:
529                 case Opt_noacl:
530                         printk("EXT2 (no)acl options not supported\n");
531                         break;
532 #endif
533                 case Opt_xip:
534 #ifdef CONFIG_EXT2_FS_XIP
535                         set_opt (sbi->s_mount_opt, XIP);
536 #else
537                         printk("EXT2 xip option not supported\n");
538 #endif
539                         break;
540
541 #if defined(CONFIG_QUOTA)
542                 case Opt_quota:
543                 case Opt_usrquota:
544                         set_opt(sbi->s_mount_opt, USRQUOTA);
545                         break;
546
547                 case Opt_grpquota:
548                         set_opt(sbi->s_mount_opt, GRPQUOTA);
549                         break;
550 #else
551                 case Opt_quota:
552                 case Opt_usrquota:
553                 case Opt_grpquota:
554                         printk(KERN_ERR
555                                 "EXT2-fs: quota operations not supported.\n");
556
557                         break;
558 #endif
559
560                 case Opt_reservation:
561                         set_opt(sbi->s_mount_opt, RESERVATION);
562                         printk("reservations ON\n");
563                         break;
564                 case Opt_noreservation:
565                         clear_opt(sbi->s_mount_opt, RESERVATION);
566                         printk("reservations OFF\n");
567                         break;
568                 case Opt_ignore:
569                         break;
570                 default:
571                         return 0;
572                 }
573         }
574         return 1;
575 }
576
577 static int ext2_setup_super (struct super_block * sb,
578                               struct ext2_super_block * es,
579                               int read_only)
580 {
581         int res = 0;
582         struct ext2_sb_info *sbi = EXT2_SB(sb);
583
584         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
585                 printk ("EXT2-fs warning: revision level too high, "
586                         "forcing read-only mode\n");
587                 res = MS_RDONLY;
588         }
589         if (read_only)
590                 return res;
591         if (!(sbi->s_mount_state & EXT2_VALID_FS))
592                 printk ("EXT2-fs warning: mounting unchecked fs, "
593                         "running e2fsck is recommended\n");
594         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
595                 printk ("EXT2-fs warning: mounting fs with errors, "
596                         "running e2fsck is recommended\n");
597         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
598                  le16_to_cpu(es->s_mnt_count) >=
599                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
600                 printk ("EXT2-fs warning: maximal mount count reached, "
601                         "running e2fsck is recommended\n");
602         else if (le32_to_cpu(es->s_checkinterval) &&
603                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
604                 printk ("EXT2-fs warning: checktime reached, "
605                         "running e2fsck is recommended\n");
606         if (!le16_to_cpu(es->s_max_mnt_count))
607                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
608         le16_add_cpu(&es->s_mnt_count, 1);
609         ext2_write_super(sb);
610         if (test_opt (sb, DEBUG))
611                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
612                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
613                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
614                         sbi->s_frag_size,
615                         sbi->s_groups_count,
616                         EXT2_BLOCKS_PER_GROUP(sb),
617                         EXT2_INODES_PER_GROUP(sb),
618                         sbi->s_mount_opt);
619         return res;
620 }
621
622 static int ext2_check_descriptors(struct super_block *sb)
623 {
624         int i;
625         struct ext2_sb_info *sbi = EXT2_SB(sb);
626
627         ext2_debug ("Checking group descriptors");
628
629         for (i = 0; i < sbi->s_groups_count; i++) {
630                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
631                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
632                 ext2_fsblk_t last_block;
633
634                 if (i == sbi->s_groups_count - 1)
635                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
636                 else
637                         last_block = first_block +
638                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
639
640                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
641                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
642                 {
643                         ext2_error (sb, "ext2_check_descriptors",
644                                     "Block bitmap for group %d"
645                                     " not in group (block %lu)!",
646                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
647                         return 0;
648                 }
649                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
650                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
651                 {
652                         ext2_error (sb, "ext2_check_descriptors",
653                                     "Inode bitmap for group %d"
654                                     " not in group (block %lu)!",
655                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
656                         return 0;
657                 }
658                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
659                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
660                     last_block)
661                 {
662                         ext2_error (sb, "ext2_check_descriptors",
663                                     "Inode table for group %d"
664                                     " not in group (block %lu)!",
665                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
666                         return 0;
667                 }
668         }
669         return 1;
670 }
671
672 /*
673  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
674  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
675  * We need to be 1 filesystem block less than the 2^32 sector limit.
676  */
677 static loff_t ext2_max_size(int bits)
678 {
679         loff_t res = EXT2_NDIR_BLOCKS;
680         int meta_blocks;
681         loff_t upper_limit;
682
683         /* This is calculated to be the largest file size for a
684          * dense, file such that the total number of
685          * sectors in the file, including data and all indirect blocks,
686          * does not exceed 2^32 -1
687          * __u32 i_blocks representing the total number of
688          * 512 bytes blocks of the file
689          */
690         upper_limit = (1LL << 32) - 1;
691
692         /* total blocks in file system block size */
693         upper_limit >>= (bits - 9);
694
695
696         /* indirect blocks */
697         meta_blocks = 1;
698         /* double indirect blocks */
699         meta_blocks += 1 + (1LL << (bits-2));
700         /* tripple indirect blocks */
701         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
702
703         upper_limit -= meta_blocks;
704         upper_limit <<= bits;
705
706         res += 1LL << (bits-2);
707         res += 1LL << (2*(bits-2));
708         res += 1LL << (3*(bits-2));
709         res <<= bits;
710         if (res > upper_limit)
711                 res = upper_limit;
712
713         if (res > MAX_LFS_FILESIZE)
714                 res = MAX_LFS_FILESIZE;
715
716         return res;
717 }
718
719 static unsigned long descriptor_loc(struct super_block *sb,
720                                     unsigned long logic_sb_block,
721                                     int nr)
722 {
723         struct ext2_sb_info *sbi = EXT2_SB(sb);
724         unsigned long bg, first_meta_bg;
725         int has_super = 0;
726         
727         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
728
729         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
730             nr < first_meta_bg)
731                 return (logic_sb_block + nr + 1);
732         bg = sbi->s_desc_per_block * nr;
733         if (ext2_bg_has_super(sb, bg))
734                 has_super = 1;
735
736         return ext2_group_first_block_no(sb, bg) + has_super;
737 }
738
739 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
740 {
741         struct buffer_head * bh;
742         struct ext2_sb_info * sbi;
743         struct ext2_super_block * es;
744         struct inode *root;
745         unsigned long block;
746         unsigned long sb_block = get_sb_block(&data);
747         unsigned long logic_sb_block;
748         unsigned long offset = 0;
749         unsigned long def_mount_opts;
750         long ret = -EINVAL;
751         int blocksize = BLOCK_SIZE;
752         int db_count;
753         int i, j;
754         __le32 features;
755         int err;
756
757         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
758         if (!sbi)
759                 return -ENOMEM;
760
761         sbi->s_blockgroup_lock =
762                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
763         if (!sbi->s_blockgroup_lock) {
764                 kfree(sbi);
765                 return -ENOMEM;
766         }
767         sb->s_fs_info = sbi;
768         sbi->s_sb_block = sb_block;
769
770         /*
771          * See what the current blocksize for the device is, and
772          * use that as the blocksize.  Otherwise (or if the blocksize
773          * is smaller than the default) use the default.
774          * This is important for devices that have a hardware
775          * sectorsize that is larger than the default.
776          */
777         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
778         if (!blocksize) {
779                 printk ("EXT2-fs: unable to set blocksize\n");
780                 goto failed_sbi;
781         }
782
783         /*
784          * If the superblock doesn't start on a hardware sector boundary,
785          * calculate the offset.  
786          */
787         if (blocksize != BLOCK_SIZE) {
788                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
789                 offset = (sb_block*BLOCK_SIZE) % blocksize;
790         } else {
791                 logic_sb_block = sb_block;
792         }
793
794         if (!(bh = sb_bread(sb, logic_sb_block))) {
795                 printk ("EXT2-fs: unable to read superblock\n");
796                 goto failed_sbi;
797         }
798         /*
799          * Note: s_es must be initialized as soon as possible because
800          *       some ext2 macro-instructions depend on its value
801          */
802         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
803         sbi->s_es = es;
804         sb->s_magic = le16_to_cpu(es->s_magic);
805
806         if (sb->s_magic != EXT2_SUPER_MAGIC)
807                 goto cantfind_ext2;
808
809         /* Set defaults before we parse the mount options */
810         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
811         if (def_mount_opts & EXT2_DEFM_DEBUG)
812                 set_opt(sbi->s_mount_opt, DEBUG);
813         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
814                 set_opt(sbi->s_mount_opt, GRPID);
815         if (def_mount_opts & EXT2_DEFM_UID16)
816                 set_opt(sbi->s_mount_opt, NO_UID32);
817 #ifdef CONFIG_EXT2_FS_XATTR
818         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
819                 set_opt(sbi->s_mount_opt, XATTR_USER);
820 #endif
821 #ifdef CONFIG_EXT2_FS_POSIX_ACL
822         if (def_mount_opts & EXT2_DEFM_ACL)
823                 set_opt(sbi->s_mount_opt, POSIX_ACL);
824 #endif
825         
826         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
827                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
828         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
829                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
830         else
831                 set_opt(sbi->s_mount_opt, ERRORS_RO);
832
833         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
834         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
835         
836         set_opt(sbi->s_mount_opt, RESERVATION);
837
838         if (!parse_options ((char *) data, sbi))
839                 goto failed_mount;
840
841         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
842                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
843                  MS_POSIXACL : 0);
844
845         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
846                                     EXT2_MOUNT_XIP if not */
847
848         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
849             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
850              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
851              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
852                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
853                        "running e2fsck is recommended\n");
854         /*
855          * Check feature flags regardless of the revision level, since we
856          * previously didn't change the revision level when setting the flags,
857          * so there is a chance incompat flags are set on a rev 0 filesystem.
858          */
859         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
860         if (features) {
861                 printk("EXT2-fs: %s: couldn't mount because of "
862                        "unsupported optional features (%x).\n",
863                        sb->s_id, le32_to_cpu(features));
864                 goto failed_mount;
865         }
866         if (!(sb->s_flags & MS_RDONLY) &&
867             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
868                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
869                        "unsupported optional features (%x).\n",
870                        sb->s_id, le32_to_cpu(features));
871                 goto failed_mount;
872         }
873
874         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
875
876         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
877                 if (!silent)
878                         printk("XIP: Unsupported blocksize\n");
879                 goto failed_mount;
880         }
881
882         /* If the blocksize doesn't match, re-read the thing.. */
883         if (sb->s_blocksize != blocksize) {
884                 brelse(bh);
885
886                 if (!sb_set_blocksize(sb, blocksize)) {
887                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
888                         goto failed_sbi;
889                 }
890
891                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
892                 offset = (sb_block*BLOCK_SIZE) % blocksize;
893                 bh = sb_bread(sb, logic_sb_block);
894                 if(!bh) {
895                         printk("EXT2-fs: Couldn't read superblock on "
896                                "2nd try.\n");
897                         goto failed_sbi;
898                 }
899                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
900                 sbi->s_es = es;
901                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
902                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
903                         goto failed_mount;
904                 }
905         }
906
907         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
908
909         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
910                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
911                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
912         } else {
913                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
914                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
915                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
916                     !is_power_of_2(sbi->s_inode_size) ||
917                     (sbi->s_inode_size > blocksize)) {
918                         printk ("EXT2-fs: unsupported inode size: %d\n",
919                                 sbi->s_inode_size);
920                         goto failed_mount;
921                 }
922         }
923
924         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
925                                    le32_to_cpu(es->s_log_frag_size);
926         if (sbi->s_frag_size == 0)
927                 goto cantfind_ext2;
928         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
929
930         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
931         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
932         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
933
934         if (EXT2_INODE_SIZE(sb) == 0)
935                 goto cantfind_ext2;
936         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
937         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
938                 goto cantfind_ext2;
939         sbi->s_itb_per_group = sbi->s_inodes_per_group /
940                                         sbi->s_inodes_per_block;
941         sbi->s_desc_per_block = sb->s_blocksize /
942                                         sizeof (struct ext2_group_desc);
943         sbi->s_sbh = bh;
944         sbi->s_mount_state = le16_to_cpu(es->s_state);
945         sbi->s_addr_per_block_bits =
946                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
947         sbi->s_desc_per_block_bits =
948                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
949
950         if (sb->s_magic != EXT2_SUPER_MAGIC)
951                 goto cantfind_ext2;
952
953         if (sb->s_blocksize != bh->b_size) {
954                 if (!silent)
955                         printk ("VFS: Unsupported blocksize on dev "
956                                 "%s.\n", sb->s_id);
957                 goto failed_mount;
958         }
959
960         if (sb->s_blocksize != sbi->s_frag_size) {
961                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
962                         sbi->s_frag_size, sb->s_blocksize);
963                 goto failed_mount;
964         }
965
966         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
967                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
968                         sbi->s_blocks_per_group);
969                 goto failed_mount;
970         }
971         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
972                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
973                         sbi->s_frags_per_group);
974                 goto failed_mount;
975         }
976         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
977                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
978                         sbi->s_inodes_per_group);
979                 goto failed_mount;
980         }
981
982         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
983                 goto cantfind_ext2;
984         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
985                                 le32_to_cpu(es->s_first_data_block) - 1)
986                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
987         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
988                    EXT2_DESC_PER_BLOCK(sb);
989         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
990         if (sbi->s_group_desc == NULL) {
991                 printk ("EXT2-fs: not enough memory\n");
992                 goto failed_mount;
993         }
994         bgl_lock_init(sbi->s_blockgroup_lock);
995         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
996         if (!sbi->s_debts) {
997                 printk ("EXT2-fs: not enough memory\n");
998                 goto failed_mount_group_desc;
999         }
1000         for (i = 0; i < db_count; i++) {
1001                 block = descriptor_loc(sb, logic_sb_block, i);
1002                 sbi->s_group_desc[i] = sb_bread(sb, block);
1003                 if (!sbi->s_group_desc[i]) {
1004                         for (j = 0; j < i; j++)
1005                                 brelse (sbi->s_group_desc[j]);
1006                         printk ("EXT2-fs: unable to read group descriptors\n");
1007                         goto failed_mount_group_desc;
1008                 }
1009         }
1010         if (!ext2_check_descriptors (sb)) {
1011                 printk ("EXT2-fs: group descriptors corrupted!\n");
1012                 goto failed_mount2;
1013         }
1014         sbi->s_gdb_count = db_count;
1015         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1016         spin_lock_init(&sbi->s_next_gen_lock);
1017
1018         /* per fileystem reservation list head & lock */
1019         spin_lock_init(&sbi->s_rsv_window_lock);
1020         sbi->s_rsv_window_root = RB_ROOT;
1021         /*
1022          * Add a single, static dummy reservation to the start of the
1023          * reservation window list --- it gives us a placeholder for
1024          * append-at-start-of-list which makes the allocation logic
1025          * _much_ simpler.
1026          */
1027         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1028         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1029         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1030         sbi->s_rsv_window_head.rsv_goal_size = 0;
1031         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1032
1033         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1034                                 ext2_count_free_blocks(sb));
1035         if (!err) {
1036                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1037                                 ext2_count_free_inodes(sb));
1038         }
1039         if (!err) {
1040                 err = percpu_counter_init(&sbi->s_dirs_counter,
1041                                 ext2_count_dirs(sb));
1042         }
1043         if (err) {
1044                 printk(KERN_ERR "EXT2-fs: insufficient memory\n");
1045                 goto failed_mount3;
1046         }
1047         /*
1048          * set up enough so that it can read an inode
1049          */
1050         sb->s_op = &ext2_sops;
1051         sb->s_export_op = &ext2_export_ops;
1052         sb->s_xattr = ext2_xattr_handlers;
1053         root = ext2_iget(sb, EXT2_ROOT_INO);
1054         if (IS_ERR(root)) {
1055                 ret = PTR_ERR(root);
1056                 goto failed_mount3;
1057         }
1058         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1059                 iput(root);
1060                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
1061                 goto failed_mount3;
1062         }
1063
1064         sb->s_root = d_alloc_root(root);
1065         if (!sb->s_root) {
1066                 iput(root);
1067                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
1068                 ret = -ENOMEM;
1069                 goto failed_mount3;
1070         }
1071         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1072                 ext2_warning(sb, __func__,
1073                         "mounting ext3 filesystem as ext2");
1074         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1075         return 0;
1076
1077 cantfind_ext2:
1078         if (!silent)
1079                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
1080                        sb->s_id);
1081         goto failed_mount;
1082 failed_mount3:
1083         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1084         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1085         percpu_counter_destroy(&sbi->s_dirs_counter);
1086 failed_mount2:
1087         for (i = 0; i < db_count; i++)
1088                 brelse(sbi->s_group_desc[i]);
1089 failed_mount_group_desc:
1090         kfree(sbi->s_group_desc);
1091         kfree(sbi->s_debts);
1092 failed_mount:
1093         brelse(bh);
1094 failed_sbi:
1095         sb->s_fs_info = NULL;
1096         kfree(sbi);
1097         return ret;
1098 }
1099
1100 static void ext2_commit_super (struct super_block * sb,
1101                                struct ext2_super_block * es)
1102 {
1103         es->s_wtime = cpu_to_le32(get_seconds());
1104         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1105         sb->s_dirt = 0;
1106 }
1107
1108 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
1109 {
1110         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1111         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1112         es->s_wtime = cpu_to_le32(get_seconds());
1113         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1114         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1115         sb->s_dirt = 0;
1116 }
1117
1118 /*
1119  * In the second extended file system, it is not necessary to
1120  * write the super block since we use a mapping of the
1121  * disk super block in a buffer.
1122  *
1123  * However, this function is still used to set the fs valid
1124  * flags to 0.  We need to set this flag to 0 since the fs
1125  * may have been checked while mounted and e2fsck may have
1126  * set s_state to EXT2_VALID_FS after some corrections.
1127  */
1128
1129 void ext2_write_super (struct super_block * sb)
1130 {
1131         struct ext2_super_block * es;
1132         lock_kernel();
1133         if (!(sb->s_flags & MS_RDONLY)) {
1134                 es = EXT2_SB(sb)->s_es;
1135
1136                 if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1137                         ext2_debug ("setting valid to 0\n");
1138                         es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1139                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1140                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1141                         es->s_mtime = cpu_to_le32(get_seconds());
1142                         ext2_sync_super(sb, es);
1143                 } else
1144                         ext2_commit_super (sb, es);
1145         }
1146         sb->s_dirt = 0;
1147         unlock_kernel();
1148 }
1149
1150 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1151 {
1152         struct ext2_sb_info * sbi = EXT2_SB(sb);
1153         struct ext2_super_block * es;
1154         unsigned long old_mount_opt = sbi->s_mount_opt;
1155         struct ext2_mount_options old_opts;
1156         unsigned long old_sb_flags;
1157         int err;
1158
1159         /* Store the old options */
1160         old_sb_flags = sb->s_flags;
1161         old_opts.s_mount_opt = sbi->s_mount_opt;
1162         old_opts.s_resuid = sbi->s_resuid;
1163         old_opts.s_resgid = sbi->s_resgid;
1164
1165         /*
1166          * Allow the "check" option to be passed as a remount option.
1167          */
1168         if (!parse_options (data, sbi)) {
1169                 err = -EINVAL;
1170                 goto restore_opts;
1171         }
1172
1173         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1174                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1175
1176         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1177                                     EXT2_MOUNT_XIP if not */
1178
1179         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1180                 printk("XIP: Unsupported blocksize\n");
1181                 err = -EINVAL;
1182                 goto restore_opts;
1183         }
1184
1185         es = sbi->s_es;
1186         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1187             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1188             invalidate_inodes(sb)) {
1189                 ext2_warning(sb, __func__, "refusing change of xip flag "
1190                              "with busy inodes while remounting");
1191                 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1192                 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1193         }
1194         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1195                 return 0;
1196         if (*flags & MS_RDONLY) {
1197                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1198                     !(sbi->s_mount_state & EXT2_VALID_FS))
1199                         return 0;
1200                 /*
1201                  * OK, we are remounting a valid rw partition rdonly, so set
1202                  * the rdonly flag and then mark the partition as valid again.
1203                  */
1204                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1205                 es->s_mtime = cpu_to_le32(get_seconds());
1206         } else {
1207                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1208                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1209                 if (ret) {
1210                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1211                                "unsupported optional features (%x).\n",
1212                                sb->s_id, le32_to_cpu(ret));
1213                         err = -EROFS;
1214                         goto restore_opts;
1215                 }
1216                 /*
1217                  * Mounting a RDONLY partition read-write, so reread and
1218                  * store the current valid flag.  (It may have been changed
1219                  * by e2fsck since we originally mounted the partition.)
1220                  */
1221                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1222                 if (!ext2_setup_super (sb, es, 0))
1223                         sb->s_flags &= ~MS_RDONLY;
1224         }
1225         ext2_sync_super(sb, es);
1226         return 0;
1227 restore_opts:
1228         sbi->s_mount_opt = old_opts.s_mount_opt;
1229         sbi->s_resuid = old_opts.s_resuid;
1230         sbi->s_resgid = old_opts.s_resgid;
1231         sb->s_flags = old_sb_flags;
1232         return err;
1233 }
1234
1235 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1236 {
1237         struct super_block *sb = dentry->d_sb;
1238         struct ext2_sb_info *sbi = EXT2_SB(sb);
1239         struct ext2_super_block *es = sbi->s_es;
1240         u64 fsid;
1241
1242         if (test_opt (sb, MINIX_DF))
1243                 sbi->s_overhead_last = 0;
1244         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1245                 unsigned long i, overhead = 0;
1246                 smp_rmb();
1247
1248                 /*
1249                  * Compute the overhead (FS structures). This is constant
1250                  * for a given filesystem unless the number of block groups
1251                  * changes so we cache the previous value until it does.
1252                  */
1253
1254                 /*
1255                  * All of the blocks before first_data_block are
1256                  * overhead
1257                  */
1258                 overhead = le32_to_cpu(es->s_first_data_block);
1259
1260                 /*
1261                  * Add the overhead attributed to the superblock and
1262                  * block group descriptors.  If the sparse superblocks
1263                  * feature is turned on, then not all groups have this.
1264                  */
1265                 for (i = 0; i < sbi->s_groups_count; i++)
1266                         overhead += ext2_bg_has_super(sb, i) +
1267                                 ext2_bg_num_gdb(sb, i);
1268
1269                 /*
1270                  * Every block group has an inode bitmap, a block
1271                  * bitmap, and an inode table.
1272                  */
1273                 overhead += (sbi->s_groups_count *
1274                              (2 + sbi->s_itb_per_group));
1275                 sbi->s_overhead_last = overhead;
1276                 smp_wmb();
1277                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1278         }
1279
1280         buf->f_type = EXT2_SUPER_MAGIC;
1281         buf->f_bsize = sb->s_blocksize;
1282         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1283         buf->f_bfree = ext2_count_free_blocks(sb);
1284         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1285         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1286         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1287                 buf->f_bavail = 0;
1288         buf->f_files = le32_to_cpu(es->s_inodes_count);
1289         buf->f_ffree = ext2_count_free_inodes(sb);
1290         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1291         buf->f_namelen = EXT2_NAME_LEN;
1292         fsid = le64_to_cpup((void *)es->s_uuid) ^
1293                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1294         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1295         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1296         return 0;
1297 }
1298
1299 static int ext2_get_sb(struct file_system_type *fs_type,
1300         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1301 {
1302         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1303 }
1304
1305 #ifdef CONFIG_QUOTA
1306
1307 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1308  * acquiring the locks... As quota files are never truncated and quota code
1309  * itself serializes the operations (and noone else should touch the files)
1310  * we don't have to be afraid of races */
1311 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1312                                size_t len, loff_t off)
1313 {
1314         struct inode *inode = sb_dqopt(sb)->files[type];
1315         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1316         int err = 0;
1317         int offset = off & (sb->s_blocksize - 1);
1318         int tocopy;
1319         size_t toread;
1320         struct buffer_head tmp_bh;
1321         struct buffer_head *bh;
1322         loff_t i_size = i_size_read(inode);
1323
1324         if (off > i_size)
1325                 return 0;
1326         if (off+len > i_size)
1327                 len = i_size-off;
1328         toread = len;
1329         while (toread > 0) {
1330                 tocopy = sb->s_blocksize - offset < toread ?
1331                                 sb->s_blocksize - offset : toread;
1332
1333                 tmp_bh.b_state = 0;
1334                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1335                 if (err < 0)
1336                         return err;
1337                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1338                         memset(data, 0, tocopy);
1339                 else {
1340                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1341                         if (!bh)
1342                                 return -EIO;
1343                         memcpy(data, bh->b_data+offset, tocopy);
1344                         brelse(bh);
1345                 }
1346                 offset = 0;
1347                 toread -= tocopy;
1348                 data += tocopy;
1349                 blk++;
1350         }
1351         return len;
1352 }
1353
1354 /* Write to quotafile */
1355 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1356                                 const char *data, size_t len, loff_t off)
1357 {
1358         struct inode *inode = sb_dqopt(sb)->files[type];
1359         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1360         int err = 0;
1361         int offset = off & (sb->s_blocksize - 1);
1362         int tocopy;
1363         size_t towrite = len;
1364         struct buffer_head tmp_bh;
1365         struct buffer_head *bh;
1366
1367         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1368         while (towrite > 0) {
1369                 tocopy = sb->s_blocksize - offset < towrite ?
1370                                 sb->s_blocksize - offset : towrite;
1371
1372                 tmp_bh.b_state = 0;
1373                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1374                 if (err < 0)
1375                         goto out;
1376                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1377                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1378                 else
1379                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1380                 if (!bh) {
1381                         err = -EIO;
1382                         goto out;
1383                 }
1384                 lock_buffer(bh);
1385                 memcpy(bh->b_data+offset, data, tocopy);
1386                 flush_dcache_page(bh->b_page);
1387                 set_buffer_uptodate(bh);
1388                 mark_buffer_dirty(bh);
1389                 unlock_buffer(bh);
1390                 brelse(bh);
1391                 offset = 0;
1392                 towrite -= tocopy;
1393                 data += tocopy;
1394                 blk++;
1395         }
1396 out:
1397         if (len == towrite)
1398                 return err;
1399         if (inode->i_size < off+len-towrite)
1400                 i_size_write(inode, off+len-towrite);
1401         inode->i_version++;
1402         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1403         mark_inode_dirty(inode);
1404         mutex_unlock(&inode->i_mutex);
1405         return len - towrite;
1406 }
1407
1408 #endif
1409
1410 static struct file_system_type ext2_fs_type = {
1411         .owner          = THIS_MODULE,
1412         .name           = "ext2",
1413         .get_sb         = ext2_get_sb,
1414         .kill_sb        = kill_block_super,
1415         .fs_flags       = FS_REQUIRES_DEV,
1416 };
1417
1418 static int __init init_ext2_fs(void)
1419 {
1420         int err = init_ext2_xattr();
1421         if (err)
1422                 return err;
1423         err = init_inodecache();
1424         if (err)
1425                 goto out1;
1426         err = register_filesystem(&ext2_fs_type);
1427         if (err)
1428                 goto out;
1429         return 0;
1430 out:
1431         destroy_inodecache();
1432 out1:
1433         exit_ext2_xattr();
1434         return err;
1435 }
1436
1437 static void __exit exit_ext2_fs(void)
1438 {
1439         unregister_filesystem(&ext2_fs_type);
1440         destroy_inodecache();
1441         exit_ext2_xattr();
1442 }
1443
1444 module_init(init_ext2_fs)
1445 module_exit(exit_ext2_fs)